This book was inspired by the short poem written by Kurt Vonnegut that appeared in the New Yorker in 2005. That poem inspired the commencement address I delivered at Georgetown University two years later, which in turn inspired me to think that the idea of "Enough" could be expanded to encompass reflections not only about money (the focus of the poem) but also about business and about life. (I should make it clear that the strong opinions I express on these issues do not necessarily reflect the views of Vanguard's present management.)

As I was considering the idea of the book, I quickly realized that I had been trancing on these ideas in a sort of uncoordinated way for at least several decades, indeed, in some sense back to my long-past youth. Indeed, many of the speeches I've delivered over the years seemed ready-made to fit into the organizing pattern that I developed for the book. Most had never been published, so putting the ideas—some old, some new, all relevant to the subject of Enough—into book form would give them an endurance possible in no other way.

I confess, however, that in perhaps a half-dozen cases, some of my words in the book and some of the quotations I've cited have appeared in my previously published works. Much as I was hesitant to do so, I concluded that if I had got it right the first time—and it amplified my theme this time—it would be foolish not to stay with the original version.

I want to thank Howard Means for helping me to pull all this material together. I also want to thank three readers of the manuscript for their helpful commentary: William J. Bernstein, neurologist, investment adviser, and prolific author, most recently of A Splendid Exchange; Andrew S. Clarke, a Vanguard principal who worked with me on Common Sense on Mutual Funds a decade ago; and Elliot McGuckin, PhD, of Pepperdine University, whose course "The Hero's Journey in Artistic Entrepreneurship and Technology" is an inspiring tribute to the relevance of classical ideals in our modern lives.

Without the help of my staff at Vanguard's Bogle Financial Markets Research Center, bringing the simple idea expressed in a short poem to its flowering into a book would have been virtually impossible. So I extend special thanks to Emily Snyder and Sara Hoffman for their efforts—always under the pressure of time—to fight their way through my inscrutable handwriting and to type and edit endlessly. I also salute Kevin P. Laughlin, my staff assistant for the past nine years, for his admirable performance, producing research on demand, checking accuracy, and making constructive editorial suggestions that made this a better book. Best of all, each of these wonderful souls did their work with infinite patience, good cheer, and professional excellence.

Speaking of patience and good cheer, I also thank Eve, my wonderful wife of 52 years, for her caring and loving support through all those years and through good times and times that were not so good, even as she wonders about my commitment to keep on battling, speaking, and writing books. Of course she's right to do so!

J.C.B.